1. Field of the Invention
The present invention relates to a device for accurately counting the number of very small projections or depressions continuously occuring on surfaces of objects, using a simple scanning means.
For example, in counting the number of sheets of a stack of paper, generally it is operated to mutually slide the paper sheets to bring their respective one edges to be staggered substantially parallel to one another and count the sheet number by turning the staggered edge portions of the paper sheets with a finger or fingers. The "very small projections or depressions on object surfaces" termed herein for purposes of the description of the present invention means continuously occurring projections of a very small height or extremely shallow depressions or grooves on a surface of an object or in embossed patterns and also such steps as being formed by successively staggering respective one edges of paper sheets in a parallel arrangement as above.
2. Prior Art
As means for determining very small variations in configuration on the surface of an object, it is known to keep a probe contacted on a surface of an intended object for determination while the object is moved and, by converting vertical motions which the probe undergoes along the surface of the object including up and down superficial changes into electric signals, carry out the intended determination.
For example, Japanese patent application Kokai publication No. 60-237310 discloses a device which includes a testing table adapted to be driven in lengthwise and breadthwise directions on a horizontal plane with a candidate object for the determination mounted thereon. In this device, a needle-type probe member for scanning in contact with a surface of the candidate object is vertically movably mounted on a carriage by a spring for adjusting the contact pressure to be applied, and an arrangement is made such that motions of the probe member are converted into electric signals to detect concave or convex changes on the surface of the object. For the means for converting the motion of the probe into electric signals, the publication under reference discloses a one in which the iron core of a differential transformer is attached to the probe to convert the motion of the probe to an electric signal and a one in which the motion of the probe is converted to an electric signal by an optical means, utilizing a laser beam.
Thus, using the above device, it is possible to count the number of for example sheets of a paper by counting the number of vertical motions of the probe after they are comverted into electrical signals, utilizing an electronic circuit.
However, conventional means for detecting projections and/or depressions on an object surface are generally very large in size and relatively complex in structure in that, as is the case with the above cited prior art device, they include a testing table for mounting a candidate object thereon, and involve the need of vertically movably supporting a probe on a carriage and also the need for a differential transformer and an optical device for detecting the vertical motion of the probe.